Selecting a good planetary gear reducer material is conducive to improving its carrying capacity and service life.
In view of the structural characteristics of the gearbox and the load properties of the gears, hard-toothed gears should be widely used. There are many ways to obtain hard-toothed gear heat treatment. Such as surface quenching, overall quenching, carbon quenching, nitriding, etc., should be selected according to the characteristics of the gear reducer.
First, surface quenching
Common surface quenching methods are high frequency quenching (for small-size gears) and flame quenching (for large-size gears). When the hardened layer of surface quenching includes the bottom of the root of the tooth, the effect is good. The flank hardness can be up to 45-55HRC.
Second, nitriding
The use of nitride can ensure that the gear in the deformation of small conditions, to achieve a high hardness and wear resistance of the flank, heat treatment is no longer good finishing, improve the carrying capacity.
Third, carbid quenching
Carbide quenching gear has a relatively large carrying capacity, but the finishing process (grinding teeth) must be used to eliminate heat treatment deformation to ensure accuracy.
Carbide quenching gear is commonly used before carbon permeation fraction of 0.2%-0.3% alloy steel, its flank hardness is often in the range of 58-62HRC, if less than 57HRC, the hard surface strength decreased significantly, higher than 62HR then brittle increased. The hardness of the carbid quenching gear is gradually reduced from the gear surface to the depth, while the effective carbon permeable depth is specified as the depth from the surface to the hardness of 5.25HRC.
The role of carbiding quenching in gear bending fatigue strength is not only to improve the hardness of the heart, but also to the residual pressure stress on the surface. It reduces the stress in the high pressure stress zone, so the root part of the tooth cannot be abrasive when grinding.